Automatic paper finishing machine



Nov. 9, 1965 5. FORRESTER AUTOMATIC PAPER FINISHING MACHINE 11 Sheets-Sheet 1 Filed March 13, 1961 IIII. QQ

INVENTOR a/wmrfamesrf/e ATTORNEYS Nov. 9, 1965 G. FORRESTER 3,216,296

AUTOMATIC PAPER FINISHING MACHINE Filed March 15, 1961 ll Sheets-Sheet 2 ATTORNEYS ll Sheets-Sheet 3 G. FORRESTER AUTOMATIC PAPER FINISHING MACHINE INVENTOR 'Q/ i/b/WQJZQ ATTORNEYS I Nov. 9, 1965 Filed March 13, 1961 Nov. 9, 1965 s. FORRESTER 3,216,296

AUTOMATIC PAPER FINISHING MACHINE Filed March 13, 1961 ll Sheets-Sheet 4 M W $54M;

ATTORNEY? Nov. 9, 1965 e. FORRESTER AUTOMATIC PAPER FINISHING MACHINE 11 Sheets-Sheet 5 Filed March 13, 1961 Nov. 9, 1965 G. FORRESTER 3,216,296

AUTOMATIC PAPER FINISHING MACHINE Filed March 15. 1961 11 Sheets-Sheet 6 INVENTOR fig M amw ATTORNEYJ 11 Sheets-sh 7 G. FORRESTER s/gem Nov. 9, 1965 AUTOMATIC PAPER FINISHING MACHINE Filed March 15, 1961 11 Sheets-Sheet 8 Nov. 9, 1965 e. FORRESTER AUTOMATIC PAPER FINISHING MACHINE Filed March 13. 1961 Nov. 9, 1965 G. FORRESTER AUTOMATIC PAPER FINISHING MACHINE ll Sheets-Sheet 9 Filed March 13. 1961 wRKEbQQ wmdsw 553m m wkwmm QEEXS IN VENTOR zlbez i fmesfiez kmmkm III-[L M WM 5 ATTORNEYS Nov. 9, 1965 G. FORRESTER 3,216,296

AUTOMATIC PAPER FINISHING MACHINE Filed March 13, 1961 ll Sheets-Sheet l0 Illllllllllllllllllllll glg 3/9 INVENTOR ATTORNEYS Nov. 9, 1965 e. FORRESTER 3,216,295

AUTOMATIC PAPER FINISHING MACHINE Filed March 13, 1961 11 Sheets-Sheet 11 INVENTOR 62%.4/ 5 f'az z eakz M 6MW ATTORNEY6 United States Patent 3,216,29 AUTOMATIC PAPER FINISHING MACHINE Gilbert Forrester, Falmouth, Maine, assignor to S. D. Warren Company, Boston, Mass, a corporation of Massachusetts Filed Mar. 13, 1961, Ser. No. 95,374 23 Claims. (Cl. 83-88) This invention relates generally to paper finishing machines which operate to inspect paper taken from a supply roll and cut into sheets of predetermined lengths and widths while at the same time sorting the sheets into separate piles of acceptable sheets and rejected sheets as determined by an inspection conducted on the continuous sheet taken from the supply roll.

Machines of this general type for inspecting a paper web, cutting it into sheets and sorting the good sheets from the bad sheets have been provided in the past. A primary objective of such machines is to provide operation which is as completely automatic as possible with the linear rate of travel of the paper through the machine as high as possible in order that the useful output of the machine may be a maximum and the cost of op eration reduced as much as practicable. A basic limitation on the operating speed of these machines is the speed with which the paper sheets hit a fixed stop in the layboy to which the sheets are delivered for piling into large piles which do not require trimming to be suitable for shipment. The maximum speed at which the leading edge of the paper sheet can hit a fixed stop without damage to the paper is approximately 145 feet per minute. In order to operate the inspection and cutting portions of the machine at a higher linear rate and yet not exceed the safe speed at which the sheets are delivered to the layboy, arrangements which provide for overlapping of the sheets have been employed. When the sheets are overlapped after they have been cut the eifective speed of the overlapped sheets is reduced by the ratio of the overlap involved.

In order for overlapping to be successful it is necessary to provide vertical separation between the trailing edge of a preceding sheet and the leading edge of the immediately succeeding sheet. This clearance in vertical position is necessary in order to avoid head to tail collisions between adjacent sheets when the fast moving sheet over takes the preceding sheet which has been transferred to a slower speed conveyor. Since sheets may be rejected at any time and any number of successive sheets may be rejected the absence of sheets in the path of good sheets may result in the progression of the good sheets on the slow conveyor beyond the point where there is adequate vertical separation between the trailing edge of the last :good sheet and the leading edge of the next good sheet. Thus control of overlap in conventional machines requires accurate speed control and accurate spacing between sheets.

The operating of the reject gate in prior art machines of this type has heretofore required an adequate separation between sheets and a synchronization of the operation of the reject gate to operate in the space between sheets.

The defect memory for sheet sorting machines has in the past generally been in the form of a rotating pin wheel which requires precise synchronization with the speed of the paper sheet moving from the unwinding stand through the cutter to the sorting apparatus in order that sheets arriving at the reject gate could be passed or rejected according to the defects detect-ed. Another form of memory which has been used to sort articles in accordance with an inspection performed thereon has been the shift register. While shift register memories 3,215,296 Patented Nov. 9, 1965 have been applied to machines which cut a paper strip and sort the sheets cut therefrom the mere application of such memories to existing machines has not resulted in a significant increase in paper handling speeds of such machines.

The primary object of the present invention is to provide a new and improved machine for cutting and sorting paper sheets from a continuous paper web which operates at a speed substantially higher than the speed of operation of current machines.

A further object of the invention is to provide a machine for cutting and sorting paper sheets which incorporates various novel arrangements for performing the required functions in order that substantially completely automatic operation can be maintained at a high speed of operation.

Another object is to provide an improved web tension control in a paper cutting and sorting machine.

A further object of the invention is to provide an improved overlapping section for a sheet feeding machine and controls therefor which permit the overlapping sec tion to accept paper fed thereto at a higher rate of speed than has heretofore been possible.

Another object of the invention is to provide overlapping sections of the sheet feeding machine for both the good and reject paper paths which are arranged substantially to reduce the overall length of the machine and add to the convenience of operation while at the same time providing positive control of the overlap in both the good and reject sections without the danger of the machine becoming fouled by head to tail collisions of sheets following either path.

-A further object of the invention is the provision of an improved retarding arrangement for sheets delivered from the overlap section of the machine to the layboy in order that the ultimate delivery speed of the sheets will be below that at which collision with a fixed stop will produce damage to the sheet.

A still further object of the invention is to provide an automatic layboy height control system whereby the layboy to which paper is delivered maintains the level of the top sheet at the optimum position for receiving sheets at high speed without fouling.

Another object of the invention is the provision of a reject gate structure and control system which permits operation of the reject gate intermediate the length of individual sheets thereby avoiding the requirement for operation of the reject gate in the space between sheets.

A still further object of the invention is to provide a device for paddling the sheets in the layboy into a uniform vertical stack which operates in conjunction with the sheet delivery and slow down system to maintain positive control of the sheet until it is in substantially its ultimate position in the layboy.

Another object is the provision of an improved layboy and sheet delivery system which provides piled sheets ready for shipment without edge trimming.

These and other objects of the invention and the attendant advantages thereof will be apparent from the following detailed description taken in conjunction with the accompanying drawings wherein:

FIGS. 1A,-1B and 1C are views in side elevation which when assembled as indicated show the overall arrangement of a complete machine in accordance with the in vention including in FIG. 1A a view in elevation of a pendulum tension sensing device and the associated control system for braking the paper web as it is fed through the machine;

FIG. 2 is an end elevation view of the delivery end of the machine;

FIG. 3 is a side elevation view of the layboy and delivery end of the machine viewed from the side opposite the view thereof shown in FIG. 1C; and including the photoelectric pile height control system;

FIG. 4 is a view in side elevation of a venturi sheet delivery device useful in the machine;

FIG. 5 is an enlarged view in side elevation of the reject gate showing its capability for operation in the region intermediate the ends of the sheet passing through the gate;

FIG. 6 is a block diagram of the shift register control system for the reject gate;

FIG. 6A is a detail of a delay adjusting device;

FIG. 7 is a block diagram of the photoelectric cell operated control system for the overlap sections of the machine;

FIG. 8 is a plan view of the reject gate;

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 8;

FIG. 10 is a fragmentary view partly in section of a vacuum retarding roll;

FIG. 11 is a sectional view taken along the line 11-11 of FIG. 10; and

FIG. 12 is a sectional view taken along the line 1212 of FIG. 2 showing the relation of the vacuum retarding roll to the paddle fingers.

The foregoing objects and advantages of theinvention are achieved in the disclosed embodiment showing a machine which has superposed oppositely directed overlap sections for providing initial slow down of sheets delivered by the high speed sheet delivery system from a paper cutter. A continuous web of paper is delivered at high speed to the cutter which cuts the web into sheets of predetermined lengths after which the sheets are oversped to provide a small predetermined spacing between sheets. The spaced sheets pass the reject gate to overlap sections which reduce the speed of the sheets by the factor involved in the overlap. Sheets which are rejected due to defects detected at the detector station are passed around a large diameter reversing roll and delivered to a similar overlap section for the rejected sheets which delivers rejected sheets to a layboy located substantially directly beneath the cutting knife station.

The operation of the gate is controlled by a shift register control system and operation of the reject gate can take place at substantially all positions along the sheet or between sheets. The only limitation on the operation of the reject gate is that the system should be adjusted not to operate the gate until the head of a sheet passing over (or under) the gate has reached a position of positive control between the high speed tapes. Actually for some types of paper the gate can be operated before the head of a sheet has advanced to a position of positive control since the inertia of the moving sheet will tend to carry the head of the sheet to the point where it can be gripped by the tapes for positive control.

The spacing between sheets is used to control the overlap sections which operate separately to feed sheets to the overlap systems and which are automatically stopped when no such sheet is being fed to the overlap conveyor. Thus constant overlap is maintained and the overlapped sheets do not progress to a point where a head to tail collision is possible since each overlap conveyor system is stationary in the absence of the delivery of sheets thereto. The speed of overlapped sheets supplied by the overlap conveyor system to the layboy is reduced by a vacuum retarding roll which operates continuously thereby delivering all of the overlapped sheets which have been re leased from the overlap conveyor irrespective of whether or not the overlap conveyor is in motion or stationary. This arrangement avoids the problem of arresting the freely moving sheets which have left the overlap conveyor or restarting them after they are arrested. The arrangement of the vacuum retarding roll at the layboy with the end paddle fingers, side paddles and the automatic height control for the top level of the paper in the layboy provides optimum conditions for even piling of the sheets with the result that paper may be piled at a maximum speed with substantial elimination of defective piling or jamming of the delivered sheets. The vacuum roll and side paddles pump air out of the pile with the result that air pillow effect is eliminated and an even edge pile is obtained which requires no trimming and is thus ready for shipment or use.

Referring now to FIGS. 1A, 1B and 1C a description of the overall machine will be given. The machine is supplied with paper from a suitable source such as roll 11 which is rotatably supported in an unwinding stand 12 where it is elevated by an hydraulically actuated elevator mechanism 13 to a position where the axis of the roll 11 coincides with chucks 14. Chucks 14 are hydraulically advanced into the axis of the roll 11 and expanded within the roll core to support the roll for rotation and supply a minimal braking force during normal rotation of the roll 11. Once the chucks 14 support the roll 11 the elevator mechanism 13 is retracted to the level of floor 15 in which position it is ready to receive the next roll when the machine is again loaded. The roll 11 is rotated to supply a web of paper 16 which is threaded through various guide, braking, drawing and control rolls as will now be described.

The web 16 is passed by an edge control 17 and over retarding or braking rolls 18, 19 which are positioned to provide contact with the paper web 16 over substantially greater than half of the peripheral area of the rolls 18, 19. The rolls 1%, 19 rotate with the application of a controlled amount of braking force applied to the axles thereof by a braking mechanism which operates in accordance with the displacement of a pendulum tension controtl device 21. The pendulum device 21 has an upper idler roll 22 which is rotatable about a fixed horizontal axis from which depends the pendulum arm 21 which supports for rotation a lower tension sensing roll 23.. The pendulum arm 21 and the roll 23 are movable about the axis of the roll 22 and are urged downward by the Weight of the roll 23 and arm 21. If desired a suitable biasing force could be provided to position the roll 23 and arm 21. The paper web 16 threaded to cross rolls 22 and 23 as shown acts in a counter-clockwise directiort against the urging of the pendulum 21 to establish a variable position for the roll 23 along the arc of pendulum 21 in accordance with the tension in the paper web 16" as it is delivered beyond the roll 23.

The web 16' next passes through a shock mounted defect detector stand 24 where the surface of the paper is examined for abrupt local thickness changes, lumps, wrinkles, voids and other defects which when detected produce an electrical signal which is utilized to reject the sheet of paper which is ultimately cut containing the defect detected in the stand 24. Any of the well known defect detectors can be employed at the stand 24 for producing a suitable electrical signal.

The paper web 16 is drawn from the roll 11 through the tensioning stand 20 and the defect detector stand 2 by press rolls 26 which are driven by a suitable controlled speed power drive. The speed of the press rolls 26 in the present machine provides for delivery of the Web 16. at a bedknife 27 at a linear speed of approximately 1100 feet per minute. The bedknife 27 operates with a rotating cutter 28 to sever the web 16 into individual sheets of lengths determined by the speed of the cutter 28 which is supported for rotation on the periphery of a rotatable drum support 29. By controlling the speed at which the drum 29 is driven relative to the press rolls 26 an effective selection of the length of the sheets cut by the machine can be obtained.

The sheets cut by the knives 27, 28 have a tendency to follow the periphery of the drum 29. To overcome this; tendency a positive delivery control is provided by a venturi head 31 which operates to exhaust a film of air along a surface 32 thereof in the desired direction of travel of the paper sheets which results in a deflection of the sheets toward the surface 32 and hence provides positive control for delivery of the leading edge of the sheets to a high speed tape transport system 33. A more detailed description of the construction and operation of the venturi delivery head 31 is given hereinafter in connection with FIG. 4 and in the copending application of Gilbert Forrester, Serial No. 78,924 filed Dec. 28, 1960, now Patent No. 3,054,613, and assigned to the assignee of present application.

The high speed tape transport system 33 comprises a set of upper tapes 34 and a set of lower tapes 35 which have contiguous portions traveling in the same direction and between which the sheets are delivered to the region of a reject gate 36. For this purpose the tapes 34 pass over a front roll 37, the axis of which is supported by a yoke 38 pivoted to an axis 39. The roll 37 is downwardly biased by spring 39 and the tape 34 is thus maintained in positive contact with the tape 35 for the continuous run to the reject gate 36 thereby providing positive control of the sheet between the tapes and to present the sheet to gate 36 while traveling in a substantially straight path. The speed with which the tapes 34, 35 are run is slightly greater than the linear speed at which the web 16 is delivered to the bed knife thereby providing a predetermined space between sheets at a subsequent point in the machine.

Conveyor system 33 and the reject gate 36 are eiTective to guide sheets delivered by the high speed tape conveyor system 33 to alternate paths. Sheets which have been cut from portions of the web 16 which contain no defects are passed over the top of the reject gate 36 to a high speed conveyor system 41. Sheets which contain defects as detected at the defect detector stand 24 are deflected to an alternate path by raising the reject gate 36 to an elevated position prior to the time the leading edge of the defective sheet arrives at the gate 36. This alternate path is defined by a tape system 42 which accepts sheets which pass below the reject gate 36 and guides them to a large diameter turn-around roll 43. Sheets which are carried around the turn-around roll 43 are delivered to high-speed conveyor system 44 for the reject sheets which is substantially identical with the high speed conveyor 41 for the accepted sheets. The high speed conveyor 41 delivers sheets to an overlap conveyor 45 and the high speed conveyor 44 delivers sheets to an overlap conveyor 46. Since the operation and construction of the high speed conveyor 41 and overlap conveyor 45 are identical with the high speed conveyor 44 and overlap conveyor 46 only one such conveyor and overlap system will be described. The corresponding elements of the other conveyor system will be designated by the respective reference numerals primed.

Referring now to the high speed conveyor 41, the system comprises tapes 47 which extend from a roll 43 directly above the reject gate 36 to a roll 49 secured to a support adjacent a layboy device 50. The tapes 47 provide the upper tapes in a high speed transport system extending between the roll 43 and 49. Operating in conjunction with the tapes 47 are tapes 51 which extend between the roll 48 and larger diameter disks 52 which are journalled on brackets keyed to shaft 77, which may be pivoted to adjust the height of disks 52. The tapes 47 and 51 are interdigitated in the region between the roll 48 and disks 52. A set of tapes 53 extending between rolls 54 and 55 provide the lower tapes in the high speed transport system. All the tapes 53, 51 and 47 comprise the high speed transport system and are driven at the same linear speed. The axis of roll 54 is rotatably supported in a yoke 255 which is pivoted on a horizontal axis 56 and the roll 54 is upwardly urged by a suitable spring 56' to press the tapes 53 against the tapes 51 and 47 directly thereabove. Sheets delivered by this high speed delivery system follow the tapes 47 into the region which is the input of the slow down and overlap system 45. Upon exiting from between rolls 52 and mating 6 corrugating rolls 40 the sheet is stiffened in the direction of travel by temporary corrugations produced by the interdigitation of disks 52 with collars on roll 40.

The overlap system 45 comprises a set of tapes 61 which is moving at adjustable speed ratios of, for example, 2:1 to approximately 4:1 with respect to the high speed tapes 47. The tapes 61 pass over rolls 62 and 63 and a retarding vacuum roll 64 which will be described in detail hereinafter. Adjustably positioned between the vaccuum roll 64 and the extreme end roll 63 are a pair of contacting catching disks 65 and rolls 66 between which the top run of the tapes 61 pass thereby to provide a catching nip to engage the leading edge of sheets delivered by the high speed delivery system 41. The range of position for the disks 65 and rolls 66 is indicated by the dotted position thereof at the right end of the tape delivery systems adjacent to layboy 50. This adjustment of the position of the disks 65 and rolls 66 may be achieved by journalling the disks 65, and rolls 66 in bracket 89 which is slidably supported on parallel longitudinal rails and moved by a rack and inion drive. Tape is maintained at all adjusted positions by an associated idler roll 67 movable with the disks 65 and rolls 66.

The adjusted position of the disks 65 and rolls 66 corresponds to the length of sheet being cut by the cutter 28 and is adjusted to provide a grip on the leading edge of a sheet between the nip of disks 65 and rolls 66 when the trailing edge of that sheet is approximately over the roller 62. The passage of a sheet to the position just described is assured by an upwardly directed air blast from a nozzle 68 which directs a continuous stream of air against the sheet to maintain it in contact with the fast moving tape 47. As soon as the sheet has reached a position where its leading edge is engaged by the nip of disks 65 and rolls 66 and the trailing edge has cleared the air blast from the nozzle 68, the leading edge is slowed down to the speed of tapes 61 with the result that the next oncoming sheet overtakes a portion of the spacing between sheets and the upward directed air blast from nozzle 63 directs the leading edge of the next sheet against the fast tapes 47. The reflected air blast from this subsequent sheet is downwardly directed and presses the trailing edge of the preceding sheet against a portion 69 of the tapes 61. Thus the trailing edge of the sheet is brought into contact with the slow tapes 61 and vacuum retarding roll 64 which continuously draws a vacuum to maintain contact with the paper and decelerate the trailing edge of the sheet simultaneously with the deceleration of the leading edge. Accordingly telescoping of the sheet is avoided since both the leading and trailing edges thereof are simultaneously decelerated to the same speed which is that of tapes 61.

The delivery of succeeding sheets to the nip of disks 65 and rolls 66 produces an overlap of the upper sheet with the lower sheet on the slow tapes 61 in accordance with the relative speeds at which the sheets move on the fast and slow tape delivery systems. As succeeding sheets are delivered by the fast delivery system 41 a continuously overlapped stream of sheets is arranged on the slow delivery system 45 which transports the stream of overlapped sheets to the end of the slow tape system at roll 63.

The overlapped sheets delivered beyond the roll 63 are free of further control by the tape systems and would ordinarily advance due to their own momentum to a stop 71 at the far side of the layboy 50 where they would fall onto the pile of previously delivered sheets accumulating in the layboy 50. In the present system the delivery speed of sheets from the low speed tapes 61 is still in excess of the safe speed at which the leading edge of the sheet can be permitted to strike the fixed stop 71. Accordingly further deceleration is required after the paper leaves the roll 63 and this deceleration is obtained by means of a second vacuum roll 72. The vacuum roll 72 is rotating at a peripheral speed of approximately feet per minute which is the maximum safe speed at which the leading edge of sheets can strike a fixed stop such as the stop 71.

Accordingly the overlapped stream of sheets delivered from the roll 63 passes over the vacuum roll 72 and only the bottom sheet thereof is effectively retarded by the action of the vacuum roll '72. As this sheet is decelerated it continues to move until it passes beyond the vacuum roll 72 and the next higher sheet will become the sheet which is decelerated by the vacuum roll 72. Thus each sheet in turn of the stream of overlapped delivered sheets will be decelerated just prior to having its leading edge hit the fixed stop '71. By providing a two-stage deceleration system for the sheets which are initially traveling at 1100 feet per minute, safe delivery against the fixed stop 71 of the layboy 50 can be achieved.

The height of the top sheet in the layboy 50 is controlled by a photoelectric sensing control system described hereinafter in detail in connection with FIG. 3. Also associated with the layboy 5t) and vacuum roll 72 are paddling fingers 73 which periodically paddle the trailing edge of sheets in the top portion of the layboy to maintain the stack uniformly vertical. In addition a ream ticket inserter 74 may be provided for marking the stack of sheets in accordance with a predetermined quantity of paper such as a ream.

The overlap conveyor 45 in the accepted sheet path is controlled by a pair of light source and photocell devices 75, 76 arranged to detect the presence of the paper sheet in the high speed delivery system 4-1. The devices 75, 1'6 may be, for example, miniature photoelectric scanners type SA-IRM manufactured by Farmer Electric Products Co., Inc., characterized by a light source arranged to project a beam of light to a surface from which it may be reflected to a light sensing element housed in common with the light source. For this purpose the photocells 75, 76 are arranged to detect reflected light from their internal sources which is reflected downwardly from a paper sheet traveling between the tapes '47 and 53 to impinge upon the photocells in devices 75 and 76. In the absence of a sheet in the high speed conveyor system 41 no light is reflected. The spacing between the sourcephotocell devices 75, 76 is adjusted to be such that it exceeds slightly the greatest spacing between sheets which is expected in normal operation of the apparatus. Thus for a normal run of good paper sheets spaced by a predetermined distance in the high speed conveyor 41 at least one of the photocells 75 or 76 will be energized at all times even when the space between sheets is positioned above the photocells. In this manner the absence of both photocell signals is necessary to indicate the absence of a sheet in the high speed system 41 and when both photocells 75, 76 fail to produce an output signal the overlap conveyor 45 is stopped. Conversely if either photocell 75 and 76 is producing an output signal the overlap conveyor 45 is started and maintained running at normal speed. In similar manner the control of the overlap conveyor 46 for rejected sheets is controlled by signals from a pair of spaced source-photocell devices 75', 76' in the high speed conveyor system 44. The operation of the control systems for the overlap conveyors 45, 46 will be described in detail in connection with FIG. 7.

Referring now to FIG. 2 an end view of the delivery end of the machine with the relationship of the paddle fingers 73 to the vacuum retarding roll 72 is shown. The fingers 73 are fixed at spaced intervals to a rocker shaft 80. The retarding roll 72 has a plurality of collars 81 in which are arranged a plurality of peripheral ports 82 which communicate with the interior of the roll 72 for drawing air into the ports 82 when they are upwardly positioned as will be more clearly described in connection with FIG. 10. The collars 81 are separated by reduced diameter portions 70 which provide recesses for the paddle fingers 73 across the discharge end of the machine. The roll 72 provides retarding force and the fingers 73 provide paddling along the entire width of the paper sheets which are piling in the layboy 50. The photocell control system for the pile height in the layboy maintains the top sheet 8 in the layboy at a controlled level indicated at 83 in FIG. 2.

The operation of the fingers 73 is controlled by a conventional reciprocating drive mechanism which drives shaft from an eccentric bearing 84 mounted on rotating shaft 211 to provide .a suitable number of paddling strokes for each sheet delivered across the surface of the retarding roll 72 as determined by the speed of shaft 211 driven by an adjustable speed drive 289 and motor 88. Also operated by the shaft 211 are side paddles 85 which are adjustably positioned on a cross bar 86 to operate with respect to the side dimensions of the pile as determined by the size sheet being processed by the machine. Shaft 87 is given a rocking motion by the action of collar 212 which carries a finger 213 extending into an eccentric groove 214 cut in slidable cam 215. The paddles 85 are supported from rocker shafts 87 by means of a plurality of parallel links which are rigidly affixed to the shaft 87 and firmly secured to the paddles 85. This rigid support for the paddles 85 maintains accurate perpendicularity of the face of the paddles 85 and prevents deflection of the paddles 85 when they press against the edge of the stacked sheets.

The rocking shaft 87 is suspended on brackets 201 which are suspended by needle bearing rollers 202 which ride on horizontal rails 85. The rails 86 have a gear rack 203 attached on the bottom edge which is engaged by pinions 204 at each end of shaft 206. A hand wheel 205 provides for rotating a shaft 206 and hence the pinions 254 to maintain the paddles 85. parallel to the center line of the machine for all adjusting widths thereof. Locking means 207 is provided for securing the adjusted position of the shaft 206. A similar position adjusting arrangement for the backstop 71 is provided by rack 208 and 'pinions 209.

The sheets are piled in the layboy 50 on a platform 91 which is supported at four corners by chain supports 92 which have their length adjusted by a suitable hydraulic actuator controlled by the pile height control system. This system is arranged to raise the platform 91 by means of hydraulic pressure and to lower the platform 91 by periodically releasing pressure in the hydraulic system in response to a photocell control system operating at the top edge of the pile to maintain the top edge pile height at the level 83 indicated in FIG. 2.

Referring now to FIG. 3 a side view of the layboy and vacuum retarding roll arrangement is shown, the view being from the side opposite that shown in FIG. 1C. Incoming sheets arrive in the direction of arrow 93 and pass over a delivering plate 94. After passing the lower roll 63 the sheets are free of positive control by the overlap tape conveyor system. The bottom sheet in the overlap stream passes over the surface of the vacuum retarding roll '72 and is in contact with the surface of the collars 81 to be gripped by the action of the suction through the ports 82 therein. This suction is only effective for the ports which are in a position at the top of the roll 72 and hence the necessary suction is maintained since these ports are substantially closed by passing sheets. The bottom sheet of the overlapped stream is thus delivered first to strike the backstop 71 of the layboy 50 and succeeding sheets are delivered to the layboy as they become the bottom sheet. The side paddles 85 are provided with a plurality of parallel rigid supports 95 as previously described to maintain the side edges of the pile even and vertical.

The backstop 71 is provided with an elongated slot 96 in which a photocell housed in common with a light source in device 97can be adjusted in the vertical direction to be positioned at the proper height for maintaining the level 83 of the piled sheets at the desired height. The photocell device 97 can be similar to devices 75, 76. The vertical position of photocell device 97 is adjusted to maintain the level 83 approximately at the height of the axis of rotation of the retarding roll '72. The light source in the device 97 is directed toward the pile of sheets and when the top edge 83 of the pile is present in the edge of the sheets reflect light into the device 97 which contains a photocell sensitive thereto to produce an output signal to a remotely positioned hydraulic controller 98. The hydraulic controller 98 releases hydraulic pressure in actuator cylinders 290 as long as a reflected light signal is received by the photocell in the device 97 thereby lowering the platform 91 and lowering the height of the top sheet level 83 until no reflected light is received by the device 97. At this point hydraulic pressure controlled by the controller 98 is no longer released and hence the hydraulic system maintains the then height of the platform 91 until a new reflected light signal is received by the device 97. The arrangement is capable of controlling the height of the level 83 within the narrow limits of the adjusted position of the device 97.

The retarding roll 72 is operated at a suitable speed by means of a motor 101 and a gear reduction device 102 which provides continuous rotation of the roll 72 irrespective of the operation of the overlap conveyors in the machine. This provides the final speed reduction for the sheets to approximately 145 ft./min.

Referring now to FIG. 4 the details of the venturi air delivery head 31 will be described. The general theory of operation of venturi air delivery heads for paper sheets is described in the aforementioned co-pending application. In the operation of the present machine the rotation of the drum 29 brings the rotating cutter bar into contact with the bed knife 27 as previously described to sever sheets of predetermined length from the paper web fed to the bed knife position. A set of tapes 103 is arranged to travel from the bed knife position 27 to the input of the high speed tape system 33. To assure that the sheets will follow the tapes 103 the venturi heads 31 are positioned between the tapes 103 with a plurality of such heads spaced across the transverse dimension of the sheets traveling through the machine. A moving film of air tangential to the surface 32 of the head 31 is obtained by supplying air under suitable pressure to the interior of the venturi heads 31 where it escapes through tangentially directed nozzles 104. This film of air tends to attract the sheet which is emerging from the bed knife 27 and this force overcomes any tendency that the sheet may have to follow the peripheral surface of the drum 29. The sheets are thus delivered to the input of the high speed tape system 33 without danger of jamming.

Referring now to FIG. 1A the operation of the web retarding rolls 18 and 19 will be described. As previously stated the web 16 traverses the rolls 18 and 19 and is in surface contact therewith over greater than 180 of the surface of the rolls 18 and 19. The web then proceeds over an idler roll 22 the rotating axis of which also provides the pivotal axis for the pendulum arm 21 supporting the tension roll 23. Thus the tension in the Web 16 at the position 16' between the tension roll 23 and the defect detector stand 24 is effective to deflect the pendulum 21 in an amount which is determined by the tension in the web at 16' and the weight of the elements 21 and 23. This position of the arm 21 may be sensed by any suitable means and applied to a controller, if desired, or directly to a suitable valve 106 which controls the supply of air from an air line 107 to a pneumatic brake control 108. The pneumatic brake control 108 controls the brake operating to apply braking force to the rollers 18 and 19 which rotate in unison and opposite directions by virtue of the gear connections of their rotating shafts provided by gears 109, 111. This control system is arranged to decrease the braking force applied to the rolls 18 and 19 as the tension in the web at 16 increases and thus deflects the pendulum arm 21 in a counterclockwise direction about the pivot axis at the shaft of idler roll 22. This action is with respect to a predetermined deflected position of the tension roll 23 from the position shown in FIG. 1A since in the straight up and down position of the pendulum 21 no force is exerted against the web 16' in the horizontal direction. Accordingly the running tension of the web 16 will deflect the roll 23 and pendulum 21 by a slight amount after which the pneumatic brake controller will operate to maintain tension in the web 16 substantially constant. This action can be obtained by adjusting the brake shoes on the rollers 18, 19 not to engage and apply braking force when the system is arranged with the pendulum 21 in a vertical position but with the brakes so adjusted that braking force is begun to be applied when the pendulum 21 is deflected by a small amount by tension in the web 16.

Referring now to FIG. 5, an enlarged view of the reject gate and associated rolls and tapes is shown. The reject gate 36 is located immediately subsequent the rolls 115, 116 which are at the downstream end of the highspeed tape system 33. The gate 36 is shown in its normal position with an upper surface 117 normally below the line of delivery of paper from between the tapes 34, 35 from the tape system 33. Sheets which are without defects are thus delivered and travel over the surface 117 toward the tapes 51 which provide the upper tapes in the second high-speed delivery system 41. Positive control of the sheets occurs at the point above the roll 54 where the tapes 51 become contiguous with the tapes 53. The roll 54, as previously described, is carried by swinging yoke 255 pivoted on an axle 56 and upwardly urged to cause the tapes 53 to engage the tapes 51 and provide positive gripping of the sheets delivered to the tape delivery system 41.

The gate 36 is arranged to be pivoted about an axis 118 in order to reject defective sheets. For this purpose, the gate 36 is moved to the alternate position indicated at 119. It will be noted that the spacing between rolls 48 and 115 and the deflected position 119 of gate 36 are arranged and the relative proportions of the parts are so constituted that there is adequate clearance above the gate 36 in deflected position 119 for a paper sheet 121 to continue without binding. Thus a sheet which has its leading edge under positive control between the tapes 51, 53 or even a sheet which has not had its leading edge reach this position but which has suflicient momentum to carry the sheet to the position of tapes 53 will continue in its normal path even if gate 36 is deflected to the position 119 in the middle of the sheet. This action is indicated by the alternate position of the sheet 121 running to the tapes 53, 51 over the gate in position 119. Similarly, a rejected sheet which is deflected by the gate in position 119 to travel downwardly toward the high-speed tape system 42 comprising tapes 122, 123 will continue so to travel if the gate 36 resumes its normal position as shown. Such a sheet is indicated at 124 and it can be seen that the sheet 124 travels with adequate clearance between the roll 116 and gate 36 and between roll 125 and gate 36, to avoid binding of a sheet being thus conveyed.

As an aid in assuring that rejected sheets will follow the proper path from the gate 36 in deflected position 119, a fixed curved deflector 126 is arranged to direct rejected sheets downwardly between the tapes 122, 123. The rejected sheets as they emerge between the tapes 34, 35 are given an initial downward deflection before striking undersurface 127 of the gate 36 by virtue of the air blast escaping through ports 128 in the undersurface 127 under the leading edge of the gate 36. Except for the ports 128, the gate 36 is formed as an airtight enclosure through which air under pressure is supplied for producing the air blast through the ports 128 which is effective to downwardly deflect the sheets emerging from the tapes 34, 35. The overall arrangement of the reject gate 36 and the asso'ciated structure is thus capable of operation from the normal position shown at 36 to the deflected position at 119 irrespective of the presence of sheets in either path and the machine can, consequently, operate the reject gate 36 in mid-sheet and the control systems hereinafter described are so operated. Thus the control systems of the present invention are not limited to operation of the reject gate 36 between the sheets passing the reject gate position, and hence the operation of the system can be correspondingly increased in flexibility, since this limitation of former sorters known in the prior art has been removed.

Referring now to FIG. 6, a description of the shift register memory for operating the reject gate 36 will be described. Referring to FIG. 6 the construction and operation of the defect memory and reject gate control will be described. As previously stated suitable defect detectors are employed to inspect the web 16 and produce an electrical signal when a defect is detected. For the purpose of illustration two such detectors are schematically shown in FIG. 6, a void detector 151 and a caliper gauge 152. The caliper gauge 152 may be set to produce an electrical defect signal for variations in the thickness of the web 16 outside predetermined limits. The defect signals may be amplified, if required, in respective amplifiers 153, 154 and applied as the input to flip-p memory stages 155, 156. The flip-flops 155, 156 are set to a ONE state by defect input signals thereto and are reset by the application of a reset pulse to inputs 157, 158' respectively. Upon the occurrence of a reset pulse to reset a previously set stage 155 or 156 an output pulse is produced which is the input signal to the first stage of six stage flipfiop shift registers 157, 158.

The shift registers 157, 158 operate conventionally to advance the state of each stage to the next subsequent stage upon the occurrence of a shift pulse input on lines 159, 160. Thus if a void is detected by void detector 151, for example, the input memory flip-flop 155 is set and upon the occurrence of a shift pulse on line 159 the memory flip-flop 155 is reset and the first stage of the shift register 157 is set. This action is repeated for each subsequent reset pulse on line 159 and hence the position of a set stage in the register 157 corresponds with the position of a defect in the web 16 at a point in the machine subsequent to the defect stand 24. In conventional shift register terminology the ONES in the registers 157 or 158 are advanced stage by stage upon the occurrence of the shift pulses on lines 159 or 160.

The shift pulses on lines 159 and 160 are derived in synchronism with the rotation of the cutter 28 but with adjustable phase relative to an arbitrary Zero point such as the position Where the'cutter 23 engages the bed knife 27 to make a cut in the Web 16. For this purpose the drive for the drum 29 is applied to drive rotary pulse g-enerators 161, 162.

The pulse generators 161, 162 may be constructed as rotary distributor-type mechanical contact devices with a fixed contact mounted on the housing and adjustable through 360 about the axis of rotation of the rotating contact. Preferably however the pulse generators 161, 162 are constructed as shown in FIG. 6A. In the pulse generator of FIG. 6A a cylindrical housing 171 is mounted for rotative adjustment by means of a Worm gear 172, manually driven by means of a knob 174. The worm 172 engages gear teeth 175 on the housing 171. Mounted on a shaft 176 is a disc 177 having a narrow radial slot 178. Fixed to the inner wall of the housing 171 and on one side of the disc is a light source 179. Aligned axially with the light source 179 on the opposite side of the disc 177 is a phototransistor, not shown, and associated circuit for producing an output pulse each time the slot 178 passes between the light 179 and the phototransistor. With this arrangement a resolution of one-half degree can readily be obtained. By pulse shaping, the reducibility of the pulse output with reference to rotation of shaft 176 can be maintained to any required degree of precision.

The ONES outputs of the last five stages of shift registers 157, 158 are connected to selector switches 181, 182 Where Wiper contacts 183, 184 can be adjusted to select the output of any register stage after the first as the signal for controlling the reject gate 36. The wipers 183, 184 are connected as inputs to a NOR 185 in an AND gate 186. An additional manual input 187 is applied to the NOR 185 for manually operated rejection of sheets. The AND 186 additionally includes a NOR 188 having an input from a reject gate opening pulse generator 189. The outputs of NORS 185, 188 are the inputs of a NOR 190. The operation of the AND 186 produces an output signal to set a flip-flop 191 only if a ONE input to the NOR 185 is present when the pulse input to NOR 188 occurs.

The two outputs of flip-flop 191are used to control the reject gate 36 by alternately energizing a down solenoid 192 or an up solenoid 193. When the flip-flop 191 is set the up solenoid 193 is energized to raise the gate 36 and reject the next sheet. To close the gate 36 a closing timing pulse generator 194 applies a reset pulse to the flipflop 191 thereby de-energizing the up solenoid 193 and energizing the down solenoid 192.

The opening and closing pulse generators 189, 194 include rotary pulse generator devices 195, 196 similar to the devices 161, 162.

The operation of the shift register memory control will now be described. A defect passing the detector stand 24 causes a defect signal to appear at the input flip-flop or 156 of the shift register 157 or 158 associated with that type of defect. This flip-flop remains set after the defect detector voltage pulse has returned to zero and is thus held or stored until the action of the shift pulse generators 161 or 162 causes it to shift to the next memory stage of the shift register.

The shift pulse generators 161, 162 and the gate opening and closing pulse generators 189, 194 are all geared to the rotary cutter drum 29 and rotate in synchronism with it. One pulse per revolution is delivered from each generator 161, 162, 189, 194. The angular positions at which the pulses are generated can be adjusted at each individual generator throughout 360. Since the paper web moves a distance equal to one sheet length during one revolution of the rotary cutter drum 29, the pulse generators 161, 162, 189, 194 all deliver one pulse each per sheet length. The phase relationship between the various timing pulses depends upon the individual generator position adjustment made by rotating knobs 174.

For any given sheet length the shift pulse generators 161, 162 are adjusted so that the shift pulse occurs just as a projected or future cut line in the web 16 is at the respective detector location. Thus defect signals are stored in flip-flop 155 or 156 while the portion of the sheet subsequent to the defect passes under a detector and are shifted to the next stage in the shift register as the tail of the defective sheet passes the detector. At the same instant, the input memory is reset and thus readied to receive defect signal, if any, during the passage of the next sheet.

The signal now representing a defective sheet, rather than appearing random in time as it does at the input to flip-flop 155 or 156, shifts from stage to stage of the registers 157 or 158 with each succeeding revolution of the rotary cutter drum 29. An output from the shift register occurs at the shift instant but delayed from the input to the first stage a time equal to that required for one sheet length of paper travel per stage of the register occurring before the output stage. The registers 157, 158 therefore accomplish only whole sheet length delays, the number of which depends upon which stage is selected as the output stage.

Since the distance from detector to reject gate 36 is known, the number of revolutions of the cutter drum 29 necessary to progress a given sheet from the detector to a position less than one sheet length before the reject gate 36 is also known. This number of revolutions is the number of stages that must be in the shift registers 157, 158. One extra stage 155 or 156 is for input storage of the defect signal until the sheet tail reaches the detector location. Different sheet lengths will require a dif- 13 ferent number of shifts since the distance from detector to gate 36 must be divided into an integral number of sheet lengths. The selector switches 183, 184 provide for this adjustment.

The defective sheet level signal from the shift registers 157, 158 appears at the input to AND 186 at the shift instant and remains until the next shift instant. At the instant this level appears the head of the defective sheet is less than one sheet length from the gate. The exact distance can readily be calculated by subtracting the product of sheet-length and number of shifts from the overall distance between detector 151 or 152 and reject gate 36. This distance less any distance the sheet travels during gate 36 actuation delay represents the maximum further delay that can take place and still make it possible to reject the sheet.

The delay or any portion of it can be accomplished through adjustment of the gate opening pulse generator 189 since the output from the AND 186 will not take place until the gate opening pulse from generator 189 occurs in conjunction with the shift register output. The signal from the AND 186 causes the output flip-flop 191 and power amplifier A to energize the reject gate solenoid 193 and the reject gate 36 opens to reject the defective sheet. The reject gate 36 is closed by the next pulse of the closing pulse generator 194 which is adjusted to operate after a delay sufficient to permit the rejected sheet to be under positive control of the tape system 42.

FIG. 6 shows two output solenoids. Operation is similar if a single spring return solenoid valve or solenoid is used to open the gate. In either case the gate up solenoid is de-energized when the output flip-flop changes state.

Provision for manual rejection is possible by applying a manual reject pulse to the AND gate and holding it for coincidence with the gate opening pulse. If desired the gate closing pulse can be temporarily disabled by the manual pushbutton to prevent the gate from closing and reopening with each cycle.

The memory system just described provides for four delays from the time a defect is detected until the gate closes after rejecting the defective sheet.

There delays are:

(1) A delay in time equivalent to the time required for the passage of the paper a distance from the defect location to the tail of the sheet containing it. This is the time existing between a detector output and the shift pulse instant. The delay automatically works in time with machine speed and occurrence of defect signal. (2) The shift register delay is equal to the time required for the passage of a whole number of sheet lengths. The number (N) is the number of whole sheet lengths that exist between detector and reject gate. The delay is thus the time between the first shift instant after the defect signal and shift constant N +1 after the defect signal. (3) The third delay is a fractional sheet length delay. It is the time lag between the shift pulse and the gate opening pulse. (4) The last delay is the time that the reject gate remains open. The interval between the gate opening and gate closing pulse is this delay. All delays are in terms of distance traveled. Thus the time is automatically varied with changes in machine speed, and adjustments for a given sheet length hold under all conditions of speed.

Referring to FIG. 8, a plan view of the reject gate 36 is shown. The reject gate 36 may actually be divided into four or more sections which are operated respectively by co-axial drive shafts 118 and 118' which are driven by suitable gears 319, 319' at either end of the reject gate 36. The division of the reject gate 36 into four transverse sections is for the purpose of permitting slitting the web 16 into four separate strips thereby to produce four sheets for each cut of the bed knife and cutter 27, 28 and selectively rejecting the slit sheets containing defects. Obviously, if only a single sheet is cut from the web 16 without longitudinal slitting, the gate sections 36 are op- 14 erated in unison. Pressure is supplied to the interior of the gates 36 by a suitable connection with a flexible air line 221.

FIG. 9 is a sectional view showing the arrangement of air tight portion of the gate 36 established by a bulkhead 222. The entire assembly is mounted on the coaxial shafts 118, 118 as previously described.

Where the reject gate 36 is to be divided into separately perable sections, air line connection between the separate sections is made by terminating each section with an airtight bulkhead of a recessed type 315 each provided with a suitable air line connecting fitting 216, and connecting each adjacent pair of fittings 216 with a flexible hose 217. The position of the connecting fittings 216 within the recessed space formed by end walls 315 is such that normal motion of the separate reject gate sections 36 is not restricted by the hose.

FIG. 7 shows a schematic arrangement of the overlap tape control systems for the overlap systems 45, 46. The control for the overlap system 45 is indicated within the dotted lines 322 with a similar system being provided for the overlap system 46 as indicated within the dotted lines 323. Since these systems are identical, only one will be shown and described. The overlap conveyor 45 for good sheets is controlled by the system 322 which comprises the photocell devices 75, 76 which direct light upwardly to the undersurface of the paper passing thereover. The reflected light from a sheet directly over the devices 75, 76 produces an output signal which is amplified by amplifier 324 for controlling a magnetic brake and clutch controller 325. When a signal is present from the photocell devices or 76 to the amplifier 324, the magnetic controller 325 is supplied a signal to cause disc 326 to be engaged by translation to a rotating magnetic clutch element 327 which is driven at the operating speed for the overlap conveyor. When neither photocell devices 75, 76 produce an output signal indicating the absence of the sheet thereabove, the amplifier 324 produces no output signal which causes the controller 324 to energize the brake clutch 328 and de-energize the drive clutch 327. Thus the disc 326 is translated to engage the brake clutch 328 and the rolls are immediately stopped in the overlap conveyor 45. A similar action is provided by the reject sheet overlap controller 323 for the overlap tape system 46 under the control of photocell devices 75', 76.

In addition to the control of the overlap tape systems 45, 46, FIG. 7 shows a sheet counter photocell 131 which actuates the sheet counter 132 for each sheet passing thereover. The sheet counter 132 is arranged to have an output for every predetermined number of sheets counted which output can be applied to operate the air valves of the ream ticket inserter device 74 which device is known in the art and will not be further described.

In FIG. 10, the details of construction of the vacuum retarding rolls 64, 64 and 72, 72 are shown. The vacuum retarding rolls comprise a tubular casing 134, the outer surface of which is formed into alternate collars 81 and reduced diameter portions 76 as previously described. The collars 81 have rubber treads 135 through which ports 82 extend terminating in a chamfered surface aperture 136 in the treads 135. The tubular casing 134 is provided with a drive pulley 137 for driving the rolls at the desired speed. The casing 134 is rotatively mounted on bearings 138, the inner race of which is supported on fixed shaft 139.

At one end of the tubular roll 134, the fixed support 1359 is a tubular shaft connected as indicated at 141 to a vacuum source and communicating with the interior of the fixed tubular chamber 144. The air seal 142 rotates and provides a sliding fit with the outer surface of shaft 139 by means of a leather sealing lip 143 or the like. The tubular shaft 139 terminates within the roll 134 by connection to stationary tube 144 which has in its upper surface a slot 145 extending the width of the roll. Extending along the edges of the slot 145 on each side thereof are small gasket strips 146 which provide an air 15 seal between the outer surface of the tube 144 and the rotating inner surface of the roll 134.

In FIG. 11, the effect of the tube 144, the slot 145 and gaskets 146 can be seen to provide suction to the ports 82 which are upwardly directed. As the roll 134 rotates, this suction is maintained on the ports 82 which are above the slot 145 to provide the retarding action on the sheet passing thereover.

In FIG. 12 an enlarged view of the roll 72 and paddle finger 73 similar to that shown in FIG. 3 is provided. As can be seen, the free end of the paddle finger 73 is recessed beneath the surface of the tread 135 on the roll 72 as provided by the reduced diameter portions '74 with which the fingers 73 are aligned. The free ends of the fingers 73 extend to the horizontal position of the axis of rotation of the roll 72 and provide in their extended position 173 the paddling action required for the back edge of the sheets in the layboy.

While a particular construction has been described it will be understood that the present invention is not limited thereto since individual features disclosed or the combination thereof required to obtain high-speed operation may be modified by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, the invention is to be limited only by the appended claims.

I claim:

1. A high speed paper finishing machine comprising an unwinding stand for supplying a continuous web of paper from a freely rotatable supply roll supported in said stand, a pair of retarding rolls over which said web sequentially passes with surface contact exceeding 180 on each of said retarding rolls, a defect inspection stand for said web, press rolls for drawing said web serially from said supply roll through said retarding rolls and said inspection stand, means for sensing the tension in said web between said retarding rolls and said press rolls, means responsive to aid tension sensing means for controlling the braking force applied to said retarding rolls to maintain said tension substantially constant, a rotary cutter for cutting said web into sheets of predetermined length, a first high speed conveyor, a venturi air delivery head for directing sheets cut by said rotary cutter to said first conveyor, a reject gate positioned to pass or deflect sheets delivered by said first conveyor between two alternate paths, a pair of superposed overlap conveyors positioned to receive sheets respectively delivered to said alternate paths, the lower of said overlap conveyors including a large diameter turn-around roll for reversing the direction of sheets prior to overlapping, means responsive to the detection of defects at said inspection stand for operating said reject gate, means responsive to the entry of a normal sequence of sheets in either of said overlap conveyors for driving that overlap conveyor during said entry, a layboy at the delivery end of each of said overlap conveyors, and a continuously rotating vacuum retarding roll at the delivery end of said overlap conveyors for retarding the tail of the lower sheet of the overlapped stream of sheets as said stream passes over said vacuum roll into the respective layboy.

2. A high speed paper feeding machine comprising an unwinding stand for supplying a continuous web of paper from a roll rotatably supported in said stand with minimal fixed drag, a pair of spaced retarding rolls over which said web sequentially passes with surface contact exceeding 180 on each of said retarding rolls, press rolls for drawing said web from said supply roll through said retarding rolls, means for sensing the tension in said web between said retarding rolls and said press rolls, and means for applying a controlled braking force to said retarding rolls in accordance with said tension to maintain said tension substantially constant.

3. A high speed paper feeding machine comprising an unwinding stand for supplying a continuous web of paper from a roll rotatably supported in said stand with minimal fixed drag, a pail Of retarding rolls, an idler roll, a pendulum frame depending from the axis of rotation of said idler roll, a tension roll rotatably supported by said frame beneath said idler roll, said retarding rolls, idler roll and tension roll being positioned for sequential passage of said web thereover with greater than surface contact on said retarding rolls and to deflect said tension roll and pendulum frame in accordance with the tension in said web, braking means on said retarding rolls, a controller for operating said braking means, means for sensing the position of said pendulum frame, and means for operating said controller in accordance with the sensed position of said pendulum frame to control the braking force applied to said retarding rolls.

4. A high speed paper feeding machine comprising an unwinding stand for supplying a continuous web of paper from a roll rotatably supported in said stand with minimal fixed drag, a pair of spaced retarding rolls over which said web sequentially passes with surface contact exceeding 180 on each of said retarding rolls, press rolls for drawing said web from said supply roll through said retarding rolls, a tension roll movably supported between said retarding rolls and said press rolls, and bearing on said web means for biasing said tension roll to a position determined equilibrium between the biasing force and the tension in said web, and means for applying a controlled braking force to said retarding rolls in accordance with the position of said tension roll to maintain tension in said web substantially constant.

5. A paper sheet cutting machine comprising a rotary cutter, means for feeding a continuous web to said cutter to be cut into sheets of predetermined length, a sheet delivery system for sheets cut by said cutter, a stationary venturi air delivery head positioned with a surface approximately tangent to the path of said rotary cutter and directed toward the input of said delivery system, and means for exhausting air from said head along said surface to attract sheets cut by said cutter and direct them toward said input of said delivery system.

6. A high speed paper finishing machine comprising means for feeding a continuous web of paper, means for inspecting said web for defects, a memory device responsive to defects detected by the inspecting means, means for cutting said web into sheets of predetermined length, a reject gate operative to direct said sheets into either one of two paths, means for operating said reject gate in accordance with defect information from said memory device, an overlap conveyor for sheets in each of said paths, means for detecting the entry of a sheet in one of said paths, means for driving the overlap conveyor in said one path during the detection of said entry of a sheet, a layboy at the end of each of said overlap conveyors, and a continuously driven vacuum retarding roll at the end of the overlap conveyor for said one path for decelerating the bottom sheet of paper from the overlap conveyor in said one path prior to delivery to said layboy for said one path.

7. A high speed paper finishing machine comprising means for feeding a continuous web of paper, means for inspecting said web for defects, a memory device responsive to defects detected by the inspecting means, means for cutting said web into sheets of predetermined length, a reject gate operative to direct said sheets into either one of two paths, means for operating said reject gate in accordance with defect information from said memory device, an overlap conveyor for sheets in each of said paths, means for driving said overlap conveyors, means for detecting the entry of a sheet in either of said paths, means for actuating said driving means for either of said overlap conveyors during the detection of the entry of a sheet in either of said paths respectively, a layboy at the end of each of said overlap conveyors, and a continuously driven vacuum retarding roll at the end of each of said overlap conveyors for decelerating the bottom sheet of paper from the overlap conveyors prior to delivery to said layboys.

8. A high speed paper sheet overlap system comprising a high speed conveyor, a low speed overlap conveyor for sheets delivered by said high speed conveyor, detecting means -for detecting the absence of a sheet in said high speed conveyor, and means responsive to said detecting means for arresting said overlap conveyor during the absence of a sheet in said high speed conveyor.

9. A high-speed paper sheet overlap system comprising a first high-speed conveyor, a reject gate positioned in the path of sheets delivered by said first conveyor, a second high-speed conveyor for sheets passing said reject gate, a low-speed overlap conveyor for sheets passing said reject gate and delivered by said second conveyor, detecting means for detecting the absence of a sheet in said second high-speed conveyor, and means responsive to said detecting means for arresting said overlap conveyor during the absence of a sheet in said second high-speed conveyor.

10. A high-speed paper sheet overlap system comprising a high-speed tape conveyor having an upper high-speed tape run extending from the source of said sheets to a point of delivery and a high-speed lower tape run extending from said source adjacent a portion of said upper run, a low-speed tape run extending beneath and spaced from the remainder of said upper high-speed tape run, a pair of catching rolls adjustably positioned along said low-speed tape run to provide a sheet head catching nip operated at the same speed as the tapes in said low-speed tape run, and a vacuum retarding roll positioned with peripheral suction ports at the level of the tapes in said low-speed tape run and located near the beginning of said low-speed tape run.

11. Apparatus according to claim and including an air blast nozzle directed upwardly between said lower highspeed run and said lower low-speed run.

12. Apparatus according to claim 11 in which the position of said catching rolls is adjusted to space said nip from said vacuum slow down roll by the length of said sheets.

13. A high-speed paper sheet overlap system comprising a high-speed tape conveyor having a high-speed upper tape run extending from the source of said sheets to a point of delivery and a high-speed lower tape run extending from said source adjacent a portion of said upper run, a lowspeed tape run extending beneath and spaced from the remainder of said high-speed upper tape run, an air blast nozzle directed upwardly and inclined in the direction of sheet travel located between said high-speed lower tape run and said low-speed tape run for maintaining the heads of sheets emerging from the adjacent portions of said highspeed tape run against the continuing portion of said highspeed upper tape run, a vacuum retarding roll with peripheral suction ports at the level of the tapes in said low speed tape run and located near the beginning of said low speed tape run to retard the tail of sheets depressed thereon by the deflection of the air blast from said nozzle directed against the head end of the next subsequent sheet, and a pair of catching rolls adjustably positioned along said lowspeed tape run to provide a head catching nip spaced from said vacuum slow down roll by the length of said sheets and adapted to catch the head of the sheet traveling on said high-speed upper tape run.

14. An overlap system for sheet material comprising means for delivering sheets at high speed over a low speed conveyor to deposit the heads of each of said sheets on said conveyor, catching roll means running at the speed of said conveyor and providing a nip on said conveyor at the position of deposit of said heads, and a tail arresting means located on said conveyor under the tails of sheets which have heads at said nip and operative to reduce the speed of the tails of each of said sheets to the speed of said conveyor.

15. Apparatus according to claim 14 in which said tail arresting means is a roll rotating at the peripheral speed of said conveyor and having suction ports in the surface of said roll effective to grip said sheets falling on said conveyor.

16. Apparatus according to claim 15 and including air blast means for deflecting the tails of said sheets against said roll.

17(Apparatus according to claim 14 in which said catching roll means are adjustably positioned along said conveyor to be spaced from said tail arresting means by approximately the length of said sheets.

18. An overlap system for sheet material comprising means for delivering sheets at high speed over a low speed conveyor, a vacuum roll having surface ports and a pcripheral speed corresponding to said conveyor operative at the surface of said conveyor beneath the point of delivery of said sheets from the sheet delivering means, means for maintaining suction at said ports in said roll, and a pair catching rolls running at the speed of said conveyor and adjustably positioned to provide a nip on said conveyor at a selected position spaced from said roll by approximately the length of said sheets.

19. Apparatus according to claim 18 and including means for directing an air blast upwardly on the under surface of said sheets between said point of delivery and said roll.

20. A high speed paper sheet overlap system comprising a first high-speed conveyor, a reject gate positioned in the path of sheets delivered by said first conveyor and movable to direct said sheets into two alternate paths, second and third high-speed conveyors respectively to receive sheets delivered to said alternate paths, a pair of low-speed overlap conveyors for receiving sheets delivered respectively by said second and third conveyors, separate detecting means for detecting the absence of a sheet in said second and third conveyors, and means responsive to said detecting means for arresting during the absence of a sheet in said second or third conveyor the overlap conveyor corresponding to the second or third conveyor in which a sheet is absent.

21. A system according to claim 20 in which said second high-speed conveyor and the corresponding overlap conveyor are positioned end-to-end to transport sheets in a substantially linear path, said third conveyor is positioned beneath and extends substantially the same horizontal distance from said reject gate as said second conveyor and corresponding overlap conveyor, said overlap conveyor for said third conveyor being positioned beneath said third conveyor and operated to transport sheets in a direction opposite to the direction of sheet flow in said second conveyor, and including a large diameter turnaround roll located substantially at the end of said third conveyor for reversing the direction of flow of sheets in said third conveyor prior to delivering said sheets to the lower overlap conveyor.

22. In a paper sheet delivery system an overlap conveyor for providing a first reduction in speed of sheets traveling through said system, means for detecting the entrance of sheets into said overlap conveyor, a vacuum retarding roll positioned at the exit end of said conveyor and beneath the stream of overlapped sheets, means for intermittently advancing said conveyor in response to the detection of sheets entering said overlap conveyor, and means for continuously rotating said roll at a peripheral speed less than the speed of said stream.

23. A high speed paper finishing machine comprising means for feeding a continuous web of paper, means for inspecting said web for defects, a memory device responsive to defects detected by the inspecting means, means for cutting said Web into sheets of predetermined length, a reject gate operative to direct said sheets into either one of two paths, means for operating said reject gate in accordance with defect information from said memory device, an overlap conveyor for sheets in each of said paths, said overlap conveyors having adjoining high and low speed tape transport systems arranged to overlap sheets at their juncture, a vacuum retarding roll having surface ports and a peripheral speed corresponding to said low speed conveyor operative at the surface of said low speed conveyor beneath the point of delivery of sheets from said high speed conveyor, means for maintaining suction on said ports, means for detecting the 

1. A HIGH SPEED PAPER FINISHING MACHINE COMPRISING AN UNWINDING STAND FOR SUPPLYING A CONTINUOUS WEB OF PAPER FROM A FREELY ROTATABLE SUPPLY ROLL SUPPORTED IN SAID STAND, A PAIR OF RETARDING ROLLS OVER WHICH SAID WEB SEQUENTIALLY PASSES WITH SURFACE CONTACT EXCEEDING 180* ON EACH OF SAID RETARDING ROLLS, A DEFECT INSPECTION STAND FOR SAID WEB, PRESS ROLLS FOR DRAWING SAID WEB SERIALLY FROM SAID SUPPLY ROLL THROUGH SAID RETARING ROLLS AND SAID INSPECTION STAND, MEANS FOR SENSING THE TENSION IN SAID WEB BETWEEN SAID RETARDING ROLLS AND SAID PRESS ROLLS, MEANS RESPONSIVE TO AID TENSION SENSING MEANS FOR CONTROLLING THE BRAKING FORCE APPLIED TO SAID RETARDING ROLLS TO MAINTAIN SAID TENSION SUBSTANTIALLY CONSTANT, A ROTARY CUTTER FOR CUTTING SAID WEB INTO SHEETS OF PREDETERMINED LENGTH, A FIRST HIGH SPEED CONVEYOR, A VENTURI AIR DELIVERY HEAD FOR DIRECTING SHEETS CUT BY SAID ROTARY CUTTER TO SAID FIRST CONVEYOR, A REJECT GATE POSITIONED TO PASS OR DEFLECT SHEETS DELIVERED BY SAID FIRST CONVEYOR BETWEEN TWO ALTERNATE PATHS, A PAIR OF SUPERPOSED OVERLAP CONVEYORS POSITIONED TO RECEIVE SHEETS RESPECTIVELY DELIVERED TO SAID ALTERNATE PATHS, THE LOWER OF SAID OVERLAP CONVEYORS INCLUDING A LARGE DIAMETER TURN-AROUND ROLL FOR REVERSING THE DIRECTION OF SHEETS PRIOR TO OVERLAPPING, MEANS RESPONSIVE TO THE DETECTION OF DEFECTS AT SAID INSPECTION STAND FOR OPERATING SAID REJECT GATE, 